Australian Severe Weather Forum

Hi Michael,

Thanks for those - they are absolutely awesome images!

A thought came to my mind though about observing the weather as Tropical Cyclone Larry approached. The spiral bands would be interested to watch considering the motion is towards but the bands are curved!

Regards,

Jimmy Deguara

Michael,
I join Jimmy in thanking you for the links to those spectacular images.

Jimmy, do you mean that the cyclone is moving towards you but the spiral bands are curving away from you, if you are standing watching the cyclone approach?

One thing that I find interesting is that on the radar, after landfall of Larry, all of the heaviest rainfall was to the north of the eye along the coast between Innisfail and Cairns. Given the direction of the winds, I would have thought the opposite would have been the case. What is the explanation for this?

Geoff

We now have another serious Cyclone. This time it's Tropical Cyclone Glenda off the north west coast. It's going through a period of intensification right now and is expected to be catagory 4 soon. It's track is a dangerous one for the coastal communities in that region as it looks like hugging the coast for at least the next 36 hours.

If you have some nice satellite pictures from tropical cyclone Glenda feel free to post them with reference to their source.

Regards,

Jimmy Deguara

Here's a 1km VIS just before sunset 28th March when the cyclone was about 925hPa. It appears to have bottomed out at 910hPa overnight.

MB

Click to enlarge

Glenda looks like it has lived up to a lot of it's potential strength. So far Mardie station has been side swipped by the cyclone and had a 180km/h gust recorded. The eye wall itself should at least have had gusts to 225km/h. Maybe Onslow will get some of the eyewall within the next coulpe of hours.

It was funny last night as I was listening to news reports of the cyclone and they said it was strengthening as it was approaching Onslow and would go on to hit Exmouth! Exmouth wasn't even in the path on the forcast map and as for strengthening, well it was actually weakening. Unless someone had a regulation wind guage out on a ship in the path of the eyewall I believe that as it passed Mardie station it was a strong Cat 3 cyclone only. Mardie recorded a 180 km/h gust within 50 km of the eye. Onslow appears to have an almost direct hit by the eyewall and recorded only a 160km/h gust. Granted though it wasn't quite in the best sector for strong winds. Still it appears to have degraded to a Cat 2 by the time it reached onslow. I very much doubt the offical Cat 4 rating all the way to Onslow.

Google Earth and tropical cyclone Larry

http://www.googleearthhacks.com/dlf...clone-Larry.htm


Tropical cyclone Larry video

http://www.youtube.com/watch?v=f9LHT7RRp-8

More information video and pictures here:

Seven News
http://seven.com.au/news/storyinfo_images_cyclonelarry

Washington Post
http://www.washingtonpost.com/wp-dyn/content/article/2006/03/19/AR2006031900302.html

http://www.washingtonpost.com/wp-dyn/content/article/2006/03/19/AR2006031900302_2.html

CBS news
http://www.cbsnews.com/stories/2006/03/20/world/main1419544.shtml


Any other links and video feel free to add more.

Regards,

Jimmy Deguara

Tropical Cyclone Monica developed in the Gulf of Carpentaria and has intensified to a category 5 as it continues to progress west. The main populated area to possibly be affected is Darwin.

Is anything left at Cape Wessel? There shouldn't be a building standing according to the alledged intensity of Monica. Again i'm not overly impressed by the measurements from this system. Either Monica was never a catagory 4 at landfall or it weakened at a phenominal pace. Maningrida aero only managed an 80knt gust and it was within sufficent distance of the eyewall in my opinion of a catagory 4 cyclone to have higher gust's than it did. I'd say it maybe managed to reach cat 4 but I personalt doubt ti ever made cat 5. The news last night nearly caused me to choke on my drink when they announced it would devestate Darwin and that it had recorded wind gusts of 350 km/h! Statements like that just prove that they really have no idea. As for the devorak method I say, dump it and start using planes like the rest of the developed world! Maybe then we'll start to see realistic wind speeds in tropical systems.

Or maybe it should have the same rating tecnique as tornadoes. If it levels to F5 intensity then it must have been F5. But if it was never measured or never destroyed anything than it was never officially rated.

Yeah it certainly didnt demonstrate features I would have anticipated of a category 5 at landfall and I am amazed at just how quickly it disintegrated today. The structure of the eye however as it passed Cape Wessell was by far the best I have seen of any Australian Cyclone this season and among the best you can get in the world. It left the eyes of other so called cat 5 cyclones for dead and the wind speed ratings given by JTWC were among the strongest I have ever seen them issue here or in the northern Pacific. I think at one stage they were going for sustained winds of 155 kts gusting to 195 kts  It would of been great though if we had Hurricane Hunters like the US to find out the true wind speeds and barometric pressure.

The media certainly has no idea when it comes to reporting weather events. They are so sensationalistic its not funny

There was some significant damage to infrastructure. One of my customers at work is Alcan Gove (Nhulunbuy). As of 28th April they do not have any phone or fax communication and email worked intermittently. The communication towers between Darwin and Nhulunbuy took a hammering and it may be many weeks before full reliable services are restored. My contacts at Nhulunbuy are just so relieved that they didn't cop a direct hit from Monica, even if she wasn't a Cat 5!

Hi,

Given Michael and a few others have a serious interest in the tropical cyclone season, perhaps a summary of this season is in order given it was far more active than the past several seasons particularl in the Coral Sea and Queensland coastline.

Regards,

Jimmy Deguara

Well, I may be new to this forum, but having read all the reports on major cyclones, and tracked the progress of all systems in the australian region(currently watching Atlantic Tropical Depression 1000nm east of the leeward isles, bout time a hurricane formed properly: Damn shear).

Disclaimer: All data is a compilation of information from JTWC, BOM, Wikipedia, and personal interpretation.

Qualification: 2nd year Meteorology student at the University of Melbourne, credited Storm Spotter for the BOM, member of ASWA(only recently), with a personal interest in all severe weather, particularly Thunderstorm systems.

Definition of Terms:

The Saffir Simpson Scale vs The Australian ranking system:
See http://www.bom.gov.au/weather/wa/cyclone/about/faq/faq_def_2.shtml
or for general system comparison http://en.wikipedia.org/wiki/Super_typhoon



2005-06 Season:

Western Australian NW shelf basin:
6 Tropical Cylones, 4 Severe Tropical Cyclones(Hurricane threshold or greater)
1 Tropical Low

Note that in this category, I do not include systems that did not achieve Tropical Cyclone(TC) status outside of the Australian Forecast area(Ie systems that moved westward).

Predictions:
As reported in Bureau of Meteorologies predictions for the NW season: 5 Cyclones, 1 of which may be severe, with two coastal impacts.

http://www.bom.gov.au/announcements/media_releases/wa/20051010.shtml

On this point the Bureau was close compared to the actual figures suggesting an average season. With higher sea surface temperatures in comparison to the previous two seasons, more systems formed, and due to the low correlation factor between the SOI and TC formation off the NW basin, it was very hard to predict a closer to exact storm pattern. (Nb that there needs to be further research into indian ocean oscillations to predict these storms).


Storm Systems:
Severe Tropical Cyclone Clare:
This System formed as a tropical low north of the Tiwi Islands(NT), moving on the common westward track, at 25km/hr(quite fast)
gained cyclone intensity 400km west of Broome, and strengthened to a category 3 system slowly over the following hours, remaining at that instensity until near coastal impact, near Dampier(WA). The system quickly lost structure and status 350km inland, probably due to the fast moving nature of the system.
Duration:7th-10th January
Tropical Cyclone status: 8pm Sat 7th
Severe:11 pm Sun 8th
Minimum Pressure: 960hPa
Maximum Saffir-Simpson: Category 1 Hurricane
Maximum Recorded Windspeed:75 knots, 140km/hr
Maximum Gust:195km/hr
Landfall Time and Category: 9th PM, Category 3 at the systems maximum strength.
Rainfall:~200mm
Disapation:11pm 10th
Comments: A fairly atypical NW Australian system, with minimal damage(mainly to power and telecommunications), some minor coastal flooding. Little recorded Storm Surge.
A full report can be found on the bureau's website.

Severe Tropical Cyclone Daryl:
A tropical low formed overland in the monsoonal trough, and moved westwards into Kuri Bay(WA). In the warm shallow water coastal enviroment the low became a tropical cyclone, and strengthed for a short period of time into a Severe system, however as the system began to be drawn southwestwards due to the coastal trough sitting along the sea breeze front, it lost its heat source, and became extratropical without actually impacting the WA coast.
Duration:17th-23rd January
Tropical Cyclone status: 17th
Severe:Briefly 21st
Minimum Pressure: ~990hPa
Maximum Saffir-Simpson: Tropical Storm
Estimated Maximum Windspeed:No ships recordings: estimated 90km/hr
Maximum Gust:less than 120km/hr
Landfall Time and Category: None
Rainfall:Neglible as a tropical low.
Disapation:23rd
Comments: This system was slightly unusual in that it formed overland, but due to its southerly position never really got started. Note that due to formation location and track, little data other than dvorak and estimations is available.

This summary of the season will continue as I review my notes.

John,

Welcome to the forum! Excellent summary - thank you for taking the time to put it together. Very much appreciated. I did find it interesting in regards to the forecast and correlations.

Regards,

Jimmy Deguara